|A) - TOTAL NUMBER OF WARNINGS ISSUED: 61
B) - NUMBER OF WARNINGS THAT DID NOT VERIFY: 33
C) - WARNED MARINE EVENTS: 29*
* = [Verified Warnings= 28(A-B) + Multiple Marine Events within same warning:= 1 ]
D) - NUMBER OF MARINE EVENTS WITHOUT WARNING: 3
TOTAL MARINE EVENTS (C+D): 32
The numbers above are used to calculate severe weather statistics, which give a measure of an office''s performance. There are 3 statistics used in severe weather verification:
1. False Alarm Ratio, or FAR, which is the ratio of unverified warnings to the total number of warnings issued. The lower the FAR the better, since it expresses the number of "false alarms" issued.
2. Probability of Detection, or POD, is the ratio of warned severe events to total severe events. A high POD is best, since it shows the skill an office has in warning for severe weather events.
3. Critical Success Index, orCSI, takes both FAR and POD into account to give a measure of performance that includes both verified and unverified events. As with POD, a high CSI is best.
An average lead time was calculated for all warnings issued this year. Lead time is defined as the time elapsed from when the warning was issued to the time of the first severe weather occurrence in the warned county.
FALSE ALARM RATIO (FAR):
|(0 is best)||UNVERIFIED WARNINGS||=||33||=||54.0 %|
PROBABILITY OF DETECTION (POD):
|(100% is best)||WARNED EVENTS||=||29||=||90.6 %|
CRITICAL SUCCESS INDEX (CSI):
|(100% is best)||WARNED EVENTS||=||29||=||44.6 %|
|TOTAL EVENTS + UNVER WRNGS||32+33|
AVERAGE LEAD TIME:23.3 minutes
Note: All data is preliminary and is subject to modification!
Questions or comments? Email Joseph.Dellicarpini@noaa.gov